Process of making wool-like artificial fibers



Patented Feb. 22, 1938 UNITED STATES PATENT OFFICE PROCESS OF MAKING WOOL-LIKE ARTI- FICIAL FIBERS I. G. Farbenindustrie Aktiengesellschaft,

Frankfort-on-the-Main, Germany No Drawing. Application December 13, 1934, Se-

rial No. 757,372. In Germany December 29,

3 Claims.

Our application Serial No. 705,474, filed January 5, 1934, relates to a new species of wool-like artificial fibers obtained by treating wet artificial fibers consisting of regenerated cellulose showing the physical properties of copper silk, with organic liquids capable of removing water until the treated fibers still contain the so-called molecular water usually present in commercial brands.

Now we have found a particularly suitable starting material for said process consisting of spun material obtained by using a viscose ripened below the usual degree of ripeness corresponding with an ammonium chloride number of 'l' to 6 (Hottenroth number).

D In this manner a distinctly wool-like fibrous material is obtained, a fact, which is particularly new and surprising in view of a process starting from a viscose product.

In order to further illustrate our invention the following example is given; but we wish it to be understood that our invention is not limited to the particular products or reaction conditions stated therein.

Example A viscose material which has been spun, while using a viscose ripened below the usual degree of ripeness corresponding with an ammonium chloride number of 6 for a further three days at 20 C., is freed continuously, either in single 30 thread or for example in hanks, from the acid and sulfur and well washed out. The excess of the adherent water then is removed by squeezing or centrifuging, and the still wet material is subjected to a treatment with methylalcohol accord- 5 ing to the counter-current principle, at the beginning with an alcohol of 55% strength, which (Cl. l854) flows oif, and at the end with alcohol of 92% strength, which flows in. The small quantity of adherent alcohol is pressed oiT or centrifuged, and the alcohol is otherwise recovered in known manner. 5

In this manner a new fiber is obtained which is distinguished by a remarkable softness, a warm touch and a crepe and curly form, thus being similar to animal fibers such as wool or natural silk.

We claim:

1. Process of making a wool-like artificial fiber which comprises treating wet fiber, which has been spun from viscose having a degree of ripeness below 7 to 6 Hottenroth, with organic liquids miscible with water.

2. Process of making a wool-like artificial fiber which comprises treating wet fiber, which has been spun from viscose having a degree of ripeness below 7 to 6 Hottenroth, with organic liquids miscible with water, the treatment being continued until the treated fiber contains only the so-called molecular water usually present in commercial brands.

3. A wool-like artificial fiber, distinguished by a remarkable softness, a warm touch and a crepe and curly form, obtained by treating wet fiber, which has been spun from viscose having a degree of ripeness below '7 to 6 Hottenroth, with organic liquids miscible with water the treatment being continued, until the treated fiber contains only the so-called molecular water usually present in commercial brands.

ARTHUR VON WEINBERG. HANNS REIN. OTTO EISENHUT. 

